Strip stock feeders



Dec. 27, 1955 A. F. GROLL 2,728,571

STRIP STOCK FEEDERS Filed Aug. 31, 1949 4 Sheets-Sheet 1 IN VEN TOR.

Dec. 27, 1955 A. F. GROLL 2,728,571

STRIP STOCK FEEDERS Filed Aug. 51, 1949 4 Shets-Sheet 2illllllllllllllll"! I, INVENTOR 46w! ATTORN YS 1955 A. F. GROLL2,728,571

STRIP STOCK FEEDERS Filed Aug. 31, 1949 lira INVENTOR.

AT ORNEYS,

Dec. 27, 1955 A. F. GROLL. ,728,57

STRIP STOCK FEEDERS Filed Aug. 31, 1949 4 Sheets-Sheet 4 IN VEN TOR.

$51 AT TO RN Ys United States Patent STRIP STOCK FEEDERS Alvin F. Groll,Napoleon, Ohio Application August 31, 1949, Serial No. 113,395

Claims. (Cl. 271-24) This invention relates to strip material feederssuch as are employed in punch presses and in particular to improvementsin the construction of such feeders and the mounting of the feeders onthe press.

Many punch presses are arranged for automatic operation and in suchpresses it is necessary that some means he provided for automaticallyadvancing the stock to be Worked the proper distance during each strokeof the press. While feeders have been designed to accomplish this resultthey are usually complicated in structure and are difficult to align sothat they accurately feed the stock while maintaining even pressureacross the width of the stock. Many of these feeders also obstructvaluable world? space around the front of the press thus making itdifficult to inspect and replace punches and dies or other equipment onthe bed of the press.

The principal object of this invention is to provide a strip stockfeeder for a press which feeder is simple to construct and yet which isvery sturdy and reliable in operation. v

Another object of the invention is to arrange the drive for strip stockfeeder so that such drive does not interfere with any of the normaloperations of the press.

Another object of the invention is to carry the pressure roll of a stripstock feeder on an eccentrically mounted axle arranged so that limitedrotation of the axle varies the spacing between the rollers.

An ancilliary object of the invention is to provide an overcenter strutand lever arrangement for rocking the pressure roller axle through asmall angle during a selected portion of the midstroke of the press.

More specific objects and advantages are apparent from the followingdescription of a preferred embodiment of the invention.

According to the invention the pressure roller of the feeder iseccentricaily journaled on an axle that is rockr able about an axisparallel to but offset from that of the pressure roller. The pressureroller and a cooperating driving roller are driven by mechanismincluding a shaft located beneath the level of the drive rollers andextending transversely of the press in the space generally behind andbelow the die plate of the press. The drive for the rollers is takenfrom the crank shaft of the press and by a gear and overnrnning clutchis converted to intermittent one way rotation of the rollers to advancethe strip block. The pressure of the pressure rollers is released byovercenter strut and lever connections that rock the pressure rolleraxle during such time as piloting punches are actively engaged inlocating the stock. This arrangement makes it possible to inspect orreplace die plates and punches without dismantling the feeder; it makesit possible to employ ordinary gears in the drive between the mainfeeder roller and the pressure roller since only small separations ofthe rollers occur during a stroke of the press; and by journaling thepressure roller on a heavy rockable axle provides a maximum of rigiditywith a minimum of material.

A specific embodiment of the invention is illustrated in theaccompanying drawings.

In the drawings:

Figure I is a side elevation of the upper portion of a press showing theimproved feeder mounted thereon.

Figure II is a front elevation of the intermediate portions of the pressshowing the location of the feeders with respect to the punch and dieblock.

Figure Ill is a plan view showing the location of the feeders and thedrive therefor with respect to the bolster or die plate of the press andthe die block mounted thereon.

Figure IV is an elevation, partly in section, as seen from the lineIV-IV of Figure II.

Figure V is a fragmentary rear elevation taken generally along the lineV-V of Figure I.

Figure V1 is an enlarged plan view of one of the pressure rollers andfragments of the supporting frame.

Figure Vii is a fragmentary end elevation as seen from the line VIlVlI'of Figure IV.

Figure VIII is a fragmentary detail taken along the line V ll-Vlli ofFigure VII.

Figure IX is a view partly in section of the strut that cooperates withan arm of the pressure roller axle to cause release of the feedingpressure during selected portions of the midstroke of the press.

These specific figures and the accompanying description are intendedmerely to illustrate the invention and not to impose limitations on theclaims.

As an example, the improved strip feeder is shown as it is employed in amechanically operated punch press. Such a press is usually constructedwith a C-shaped frame 1 such as may be seen in Figure I. A crank shaftand connecting rod, not shown in the figure, are included in the upperportion of the press and arranged to drive a punch carrier 2 which is'in the nature of a cross-head carried in ways in the front upper face ofthe C-shaped frame 1. The lower face of the punch carrier 2 is fitted toreceive a chuck 3 in which various punches or other tools may bemounted. A bolster 4 (see also Figure II) is securely mounted from thebottom portion of the 6- shaped frame 1 in such position that it maysupport a die plate and die 5 in position to cooperate with a work punch5 and piloting punches 7 carried from the punch block 3. The die and dieplate 5 and punch 6 are shown generally since their particularly shapevaries according to the article being formed.

Any conventional drive may be employed to drive the crank shaft of thepunch and since such drives are well known none is illustrated in thedrawings.

Referring now to Figure II in particular, the complete feeder preferablycomprises two feeder assemblies 8 and 9 that are mounted one on eitherside of the die plate 5 and preferably from either the bolster 4 or anextension ofthe die plate 5. If desired the feeder assemblies 8 and 9may be rigidly mounted in spaced apart relation on a separate base thathas a flat center section that may be substituted for the bolster 4 orinterposed between the bolster and the die plate 5.

The feeder assemblies 8 and 9 include sturdy generally U-shaped frames10 and. 11 in which feeder rolls 12 and pressure rolls 13 are mounted.The feeder rolls 12 are mounted on heavy shafts 14 (see also Figure IV)that are journaled in the frames 10 and 11 with the upper surfaces ofthe rolls 12 at substantially the same level as the face of the die onthe die plate 5. The feeder roll shafts 14 are each provided with aspiral gear 15 (see Figures IV and V) that meshes with a spiral gear 16mounted on a drive shaft 17. The drive shaft 17 passes beneath and atright angles to the feeder roll shafts 14 and the gears 15 and 16 are ofsuch size that the drive shaft 17 is located near the same level as thebottom of the bolster 4 thus placing it well below the die and die plate5.

Referring to Figure III it will be noticed that the drive shaft 17passes between the bolster 4 and the back of the opening in the C-shapedportion of the press frame 1. This location for the drive shaft 17 isparticularly advantageous because it is out of the way of any chutesthat may be used to direct finished articles from the die through anopening in the back of the press frame as is sometimes done and it isnot in a position to bar access to the die and punch. Thus the die andpunch may be inspected or changed at will without dismantling anyportion of the feeder.

The drive shaft 17, within the limits of the U-shaped frame 11, carriesan overrunning clutch and gear assembly 18 to the gear of which mesheswith a rack 19. The upper end of the rack 19 is pivotally connected toan adjustable crank pin 20 of a crank 21 mounted on the end of the crankshaft of the press. The adjustable crank pin 20 may be moved along aslot 22 to adjust the length of the stroke of the rack 19. A rack guide23 pivotally mounted on the drive shaft 17 or a bushing concentrictherewith serves to hold the rack 19 in mesh with the gear of theassembly 18 even though the rack rod executes a connecting rod motionbecause of its connection to the crank arm 21.

The crank arm 21 is angularly oriented with respect to the main crank ofthe press so that the rack rod 19 reaches anend of its stroke atgenerally the same time that the pilot punches 7 are ready to enterpreviously punched pilot holes in a strip of stock or sheet material 24being fed through the press. The direction of engagement of theoverrunning clutch and gear assembly 18 and the orientation of the crankarm 21 is such that the drive shaft 17 is driven from the time that thepunch leaves the work on its upward stroke until it is again approachingthe work near the middle of its down stroke.

Referring to Figures I and V, a brake drum 25 is mounted on the end ofthe drive shaft 17 and a pair of brake shoes 26 and 27 pivotally mountedfrom a stud 28 are arranged to cooperate with the brake drum 25. Thepressure of the brake shoes 26 and 27 is controlled by a helicalcompression spring 29 that is circumjacently mounted on a bolt 30 passedthrough openings in the free ends of the brake shoes 26 and 27, thespring being held compressed between the end of the brake shoe 27 and anut 31 on the bolt 30. This brake provides suflicient retarding torqueon the drive shaft 17 to overcome the inertia of the drive rolls 12 andthe strip stock which would otherwise cause the strip to overrun and thedrive shaft 17 to coast ahead of the position determined by the drivefrom the rack rod 19 through the gear and overrunning clutch assembly18.

Referring now to Figures IV, VI, VII and VIII each upper roller 13, thepressure roller, is journaled on a divided axle 32 having sections 32aand 32b carried in the corresponding ones of the U-shaped frames 10 or11. As shown in Figure VI, a tenon 32c projecting axially from the axlesection 3217 fits into a bore 32d of the axle section 32a to hold thesections in axial alignment. One or more keys 32c loosely fitted intokeyways in the tenon 32c and bore 32d serve as a positive clutch topermit limited rotary movement of one axle section with respect to theother. The support for the axle 32 comprises a pair of sturdy pins 33and 34 inserted through holes in the upstanding ends of the frame 10 toengage aligned holes 35 and 36 drilled into the ends of the axle 32 andoffset from its axis. The pressure roll 13, in the form of a sleeveslipped over the axle 32, is carried by roller bearings 37 to minimizethe friction between the sleeve forming the roll 13 and the axle itself.At one end each pressure roll 13 is provided with a. gear 38 that mesheswith a gear 39 (Figure IV) carried on the shaft 14 supporting thecooperating drive roll 12.

A two armed plate 40 is welded to one end of the axle 32 with one of thearms extending upwardly to engage one end of an extensible strut 41 andwith the other arm extending generally horizontally to receive the upperend of a heavy tension or compression spring 42 the lower end of whichis fastened at the bottom of the U-shaped frame 10.

At the other end of the axle 32 a second plate 43 is welded to the axle,this plate 43 having a laterallycxtending arm that receives the upperend of a spring 44 which, like the spring 42, is also fastened at thebottom of the U-shaped frame. The springs 42 and 44 act as resilientmembers tending to rotate the eccentrically mounted axle 32 in adirection to force the pressure roll 13 against the drive roll 2. By theuse of a two section shaft 32 like pressures are exerted over thecomplete width of stock.

The use of the connecting clutch allows the releasing of i the roll tobe effected from one end only of the shaft 32. Also, if it is desirableto actuate roll release from both ends the connecting clutch, the key32c or its equivalent, may be eliminated.

It is immaterial insofar as operation of the feeder is concerned whetherthe axle supporting pins 33 and 34 are rigidly set in the frame 10 or inthe axle 32. From a constructional point of view it is preferable tolock the pins in the frame 10 so that by removal of the pins thepressure roll may be removed without further dismantling of the device.If the pins were positively secured in the axle itself it would benecessary to use split hearings in the frame thus complicating theconstruction of the frame of the feeder.

It was mentioned earlier that the pressure of the pressure roll 13 onthe stock 24 is released, at least momentarily, at the end of thefeeding stroke to permit the locating or pilot punches 7 to position thestock 24 and thus correct small errors in feed which would otherwise bewasteful of material. According to the invention this releasing movementis obtained by connecting the upper ends of the two armed plates 40through extensible struts 41 to a bracket 45 bolted to the punch carrier2. The bracket 45 is arranged at an elevation such that the struts 41are level (extend at right angles to the direction of movement of thepunch) as the centering punches 7 enter the material. The lengths of thestruts are adjusted so that at this point the axles 32 and the plates 40welded thereto have rotated far enough to raise the pressure rollers 13olf the stock 24. As the punch continues its downward movement thestruts 41 permit the axle 32 to rotate forwardly again thus applyingpressure to the now stationary strip stock 24. This pressure serves nouseful purpose but it is preferable to allow the struts 41 to operatepast center rather than to attempt to hold the pressure rollers 13 outof contact with the strip stock during the entire lower half of thestroke of the press. Cam or other more com- 7 plicated mechanism wouldbe required if the rolls were to be held separated a small distance andstill separated at midstroke of the press. The overcenter strut permitsthe small separation when necessary and thus makes a very simpleworkable structure.

A long stroke of the punch carrier 2 above or below midstroke toaccommodate long punches is permitting without interfering with theaction of the strip stock feeders since the struts 41 are extensible.Thus as the punch carrier 2 moves up and down from its midposition theparts of the struts separate, one sliding within the other.

The construction of the strut itself is shown in detail in Figure IX-This strut comprises a tube 46 that is pivotally connected to thebracket 45 and that slidingly receives a stem 47 threadedly engaged in acoupling 48 that is pivotally connected to the upper end of the verticalarm of the plate 40. A lock nut 49 holds the stem 47 in its adjustedposition. A collar 50 may be provided on the stem 47 to abut the end ofthe tube 46 when the strut is required to rock the axle 32 to releasethe pressure. Alternatively the collar 50 may be omitted and the end ofthe stem 47 allowed to bottom in the hole in the tube 46. If the latterconstruction is employed the tube must be vented as by a hole 51 topermit the escape of air. As illustrated inthe drawing the vent 51 islocated a short distance from the bottom of the hole so that a smallamount of air is entrapped to act as a shock absorber and soften theengagement of the two parts of the strut as the strut is shorteningduring the approach of the punch to its midposition.

By arranging the struts to release the pressure of the pressure rollers13 only during that portion of the stroke when the stock 24 is beinglocated in punching position the separation of the rollers is minimizedand there is no danger of disengagement of the gears 38 and 39 thatdrivingly connect the drive roller 12 and pressure roller 13.

It is sometimes desirable to stop the feeding action of the feederswithout stopping the press or it may be required to stop the feedingaction of one of the feeders while allowing the other to continue. Toprovide this manual control handles 52 are provided on the front side ofeach of the U-shaped frames and 11 the handles being carried on shortshafts 53 (Figure VIII) set in the U-shaped frames. The other ends ofthe shafts 53 are cut to provide a shoulder 54 that engages a lug 55welded to the twoarmed bracket 40. The cut end of the shaft 53 serves asa cam which when in the position shown allows the pressure roller 13 tobear on the drive roller 14 and which when the shaft 53 is turned pushesupwardly on the lug 55 thus rocking the axle 32 until the pressureroller 13 is raised out of contact with the strip stock 24 being fedthrough the feeder.

The strip stock feeder illustrated in the drawings is very easy toconstruct and with a minimum of material provides a very rigidstructure. The principal reason for the rigidity of the structure is thefact that an extremely sturdy axle is given considerable rotativemovement on offset axes to move the pressure roller through a smalldistance. This provides a much more rigid structure than may possibly beobtained with a yoke that is moved through a very small angular movementin positioning the pressure roller. Likewise the structure is verysimple to manufacture because there are few parts to become misalignedand none of the parts need be manufactured to extremely closetolerances.

Various modifications may be made in specific details of constructionwithout departing from the spirit and scope of the invention.

Having described the invention, I claim:

1. In a punch press having a die plate and a vertically reciprocatingpunch, a strip feeder comprising, a frame mounted at an end of the dieplate of the press, a lower roller carried on a shaft journaled in theframe, means for driving the shaft, an axle, means mounted in the frameand axle for pivotally supporting the axle, an upper roller journaled onthe axle with its axis of rotation parallel to and displaced from thepivoting axis of the axle, means for drivingly connecting the upper andlower rollers, an arm attached to the axle and having a portionextending upwardly resilient means attached to the arm for urgingpivotal rotation of the axle to force the rollers together, andextensible means connected to the arm and to a moving member of thepress the path of which extends to either side of a plane that is normalto the path and that passes through the end of the arm for rocking saidaxle against the force of the resilient means during selected portionsof the stroke of the press.

2. In a strip feeder, in combination, a frame, a lower roller carried ona shaft journaled in the frame, an axle pivotally mounted in the frame,an upper roller rotatably mounted on the axle with the axis of rotationeccentric to the rocking axis of the axle, said axle being divided between the ends of the upper roller, means for holding the sections ofthe axle in axial alignment and providing limited relative rotationtherebetween, and resilient means for urging rotary movement of eachaxle section to bring the rolls together.

3. In a strip feeder, in combination, a frame, a lower roller carried ona shaft journaled in the frame, an axle pivotally mounted in the frame,an upper roller rotatably mounted on the axle with the axis of rotationeccentric to the rocking axis of the axle, said axle being dividedbetween the ends of the upper roller, means for holding the sections ofthe axle in axial alignment and resilient means for urging rotarymovement of each axle section to bring the rolls together.

4. In a strip feeder, in combination, a frame, a lower roller carried ona shaft journaled in the frame, an axle pivotally mounted in the frame,an upper roller rotatably mounted on the axle with the axis of rotationeccentric to the rocking axis of the axle, said axle being dividedbetween the ends of the upper roller, means for holding the sections ofthe axle in axial alignment, resilient means for urging rotary movementof each axle section to bring the rolls together, and means for rockingthe axle sections against the action of the resilient means fordisengaging the feed.

5. In a punch press having a die plate and a vertically reciprocatingpunch, a strip feeder comprising, a frame mounted at an end of the dieplate of the press, a lower roller carried on a shaft journaled in theframe, an axle, pins engaged in holes in the frame and in holes in theaxle eccentric to the axis of the axle for pivotally supporting theaxle, an upper roller journaled on the axle, means for driving therollers, an arm extending radially from the axle and generally parallelto the path of the punch of the press, resilient means operativelyconnected to the axle for urging the rollers into contact and for urgingthe arm toward the path of the punch, and an extensible strut that isconnected between the arm and a part of the punch located such that thestrut is generally perpendicular to the path of the punch as the punchengages the work, said strut having a minimum length such that said axleis rotated to separate the rolls slightly before the punch first engagesthe work.

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